copilot-instructions vitest.instructions.md

A set of instructions for writing front-end unit and integration tests with Vitest, a JavaScript testing tool. It defines where tests go, how they are named and grouped, and which interaction and accessibility practices to follow.

In plain words
What is it for?
Use it to guide tests for components and functions, including test file locations, describe and it blocks, explicit imports, user interactions, and accessible element queries.
Why use it?
It helps keep tests consistent, readable, and easier to find as a front-end project grows.

Instructions file for GitHub Copilot

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add instructions/pplancq/copilot-instructions/vitest
Clone the repo
git clone --depth 1 https://github.com/pplancq/copilot-instructions

Made for: GitHub Copilot.

Per session 1,094 This file is loaded in full into every session.
When invoked 1,094 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.01094 $0.01094
Opus 5 $0.00547 $0.00547
Sonnet 5 $0.00219 $0.00219
Haiku 4.5 $0.00109 $0.00109

Measured 3d ago against content hash 88ecb0dd829b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

copilot-instructions vitest.instructions.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.github/instructions/vitest.instructions.md · 108 lines

How it starts

The opening of the file, as written. The whole thing — 108 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Vitest Testing Instructions (Front)

Purpose

Ensure the quality, readability, maintainability, and accessibility of unit and integration tests in the front-end with Vitest, following the project's best practices.

Structure and Organization

  • Tests must be placed in the tests folder at the same level as src, following the same directory structure as the source code. For example, if a component is located at src/components/Button.tsx, its test must be placed at tests/components/Button.test.tsx.
  • The test file name must follow the format: <ComponentOrFunctionName>.test.ts(x).
  • Tests must always be grouped in a describe, with sub-describe blocks if needed (maximum 2 levels).
  • Each test must use the format: it('should ...', () => { ... }).
  • Tests and examples must always be written in English.

Imports and Tools

  • Always explicitly import Vitest functions (describe, it, expect, etc.).
  • Always use userEvent from Testing Library to simulate user interactions.
  • Always prefer getByRole queries with the associated label name to target elements.
  • Always use available accessibility assertions (toHaveAccessibleName, toBeInTheDocument, toBeVisible, toHaveAccessibleDescription, toHaveAccessibleErrorMessage, etc.) to check element accessibility.
  • Always use toHaveAccessibleName to check accessibility links if available.

Accessibility (a11y)

  • Systematically check accessibility points (a11y): presence of roles, labels, accessible error messages, etc.
  • Check the visibility, validity, and accessibility of interactive elements.
  • Tests must cover error and validation cases, ensuring messages are accessible (aria-describedby, aria-invalid, etc.).
  • Always test keyboard navigation and the presence of landmarks (banner, main, contentinfo, etc.).
  • Refer to RGAA and WCAG 2.2 instructions (see .github/instructions/a11y.instructions.md).

API and Mocks

  • For API calls, exclusively use MSW (Mock Service Worker).
  • API mocks are placed in the folder: <front project root>/mocks.
  • Only mock external dependencies (hooks, browser, etc.) when relevant for test isolation or stability. Avoid over-mocking.

Read the full file on GitHub · 108 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 108 lines · 1,094 tokens per session scan A 88ecb0dd829b

Subscribe to this mod's changes

copilot-instructions vitest.instructions.md is an instructions file published in the GitHub repository pplancq/copilot-instructions (4 stars, last pushed 7mo ago), licensed MIT. It adds 1,094 tokens to every session, about $0.0055 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.